Facile preparation of core-shell Ag@SiO2 nanoparticles and their application in spectrally splitting PV/T systems

Abstract

Several researchers have demonstrated that plasmonic nanofluids based filters can potentially enhance hybrid solar photovoltaic/thermal (PV/T) systems performance. In this work, we report a facile process for achieving silica-coated silver (Ag) nanoparticles using dimethylamine (DMA) as a basic solvent to induce tetraethyl orthosilicate (TEOS) hydrolysis. Then, the prepared Ag@SiO2 nanoparticles which have a controllable silica shell thickness are suspended in propylene glycol-CoSO4 hybrid fluid. Finally, the characteristics of the PV/T system filtered by the Ag@SiO2/CoSO4-PG nanofluids are evaluated based on the indoor test and photo-thermal conversion model. The results show that the nanoparticles prepared under optimized conditions, i.e., pH value of 8–9, water: ethanol volume ratio of 1:4, temperature of 25 °C, TEOS volume of 0.05 mL, and reaction time of 12 h, exhibit an absorption peak at 474 nm. Further, this study reveals that Ag@SiO2/CoSO4-PG nanofluid filter with concentration of 25.4 mg/L gives a reasonable spectral match with silicon concentrator solar cell according to the measured optical transmittance and the calculated filtering efficiency of 39.3%. The use of 25.4 mg/L Ag@SiO2/CoSO4-PG nanofluid filter produces a higher total efficiency of 63.3% and yields economic value enhancement of 67.8% compared to the PV only system when worth factor (w) is 3.